Experimental evaluation of the impact of the interactions of CO2‐SO2, brine, and reservoir rock on petrophysical properties: A case study from the Ketzin test site, Germany

The objective of this study is to evaluate the impact of impure CO2 on a possible CO2 repository. Here we present experimental data on the simulation of the injection of pure CO2 and CO2 and cocontaminant SO2 into a saline aquifer. Long‐term exposure experiments with pure CO2 reveal no significant changes in the petrophysical properties (electrical resistivity, elastic wave velocity, and permeability). In contrast, for the injection of CO2 and cocontaminant SO2 (1 vol %) we have observed significant and irreversible changes of all monitored physical parameters. On the one hand, the decrease of P wave velocity and the increase of electrical resistivity indicate a dissolution of some framework material. On the other hand, the decrease of permeability points to the mobilization and redistribution of fines. These data might be relevant for subsequent modeling and estimations about tolerable concentration limits regarding the contaminants of CO2 to be stored.